The present invention relates to a cutter control apparatus for controlling the position in which a workpiece is cut by a cutter, and more particularly to a cutter control apparatus having a correction device for automatically correcting the cutting position to make uniform the cut dimension of a piece cut by the cutter.
Heretofore, there has been available only a cutter control apparatus as shown in FIG. 1 of the accompanying drawings which has no correction device of the type described above. The cutter control apparatus as illustrated in FIG. 1 comprises a workpiece dimension detector 1 for detecting a dimension of a workpiece to be cut, a cut setting unit 2 for setting a reference dimension to be cut, a cutter control circuit 3 for comparing the detected dimension from the workpiece dimension detector 1 with the reference dimension setting from the cut setting unit 2 and for actuating a cutter of a cutting machine (not shown) when the dimensions compared are in agreement, a cut calculating circuit 4 for calculating the dimension of a piece actually cut by the cutting machine under the control of the center control circuit 3, and a display unit 5 for displaying the actual cut dimension as detected by the cut calculating circuit 4.
The operation of the cutter control apparatus of the foregoing construction for controlling the cutting machine will now be described. In addition, the manner of detecting and dealing with an erroneous actual cut will also be described. When the dimension as detected by the workpiece dimension detector 1 coincides with the (reference) cut dimension setting entered from the cut dimension setting unit 2, the cutter control circuit 3 actuates the cutter to cut off the workpiece to the set dimension. The actual cut dimensions however tend to disagree with the (reference) cut dimension settings, and are distributed in a certain range depending on a number of factors. The operator samples the dimensions of a plurality of cut pieces as calculated by the cut measuring circuit 4 and displayed by the display unit 5. The distribution of the actual cut dimensions is then determined by way of a statistical method, e.g. using a frequency table. If it is judged from the dimension distribution that a particular cut dimension is abnormal, then the operator corrects the control of the cutting position in the cutter control circuit 3 to avoid the production of a defective cut piece.
Therefore, upon a cutting malfunction, the corrective action in the conventional cutter control apparatus has been effected maunally by the operator. Such manual correction is disadvantageous in that a long period of time elapses after an abnormal cut has been made and before it is detected or the control is corrected. By the time the abnormal cut is detected and the control corrected, the defectively cut piece has already been delivered to downstream sections for successive steps. Accordingly, all operations done on the defective piece in the downstream sections become useless. Since defectively cut pieces are successively delivered until the abnormal cutting is detected, the rate of production of defective pieces, i.e. the ratio of defective pieces to normal pieces, is increased, thus increasing the cost of the products. Further, such defective products sometimes find their way into the hands of consumers, and the credibility of the products that took a long time to establish is damaged.